Title:
LENS FOR SPECTACLES AND PRODUCTION THEREOF
Document Type and Number:
Japanese Patent JPH04218016
Kind Code:
A
Abstract:
PURPOSE:To provide the lens which is free from optical aberrations, has a wide practicable visual field and is light in weight by forming an objective surface of an aspherical face to a concave shape. CONSTITUTION:A glass mold 1 and a glass mold 2 are fitted to a gasket 3 to constitute a shell 4 for casting. A raw material essentially consisting of a thermosetting resin of an urethane system is packed from an injection port 5 into this shell and is cured by heating to form the semi-finished lens having an object face and an eyepiece face. The objective face side of the lens is formed so as to have the aspherical concave shape. The eyepiece face of this semi-finished lens is worked by spherical polishing to form the finished lens having 1.5mm center thickness of the lens, -13D lens diopter and 70mm lens diameter. The optical aberrations are improved and further, the radius of curvature on the eyepiece face side is increased and, therefore, the visual field is widened and the lens thickness of the part in contact with the frame part is reduced when mounted to a spectacle frame. The weight of the lens is thus reduced.
Inventors:
SAITO SUKEYOSHI
Application Number:
JP26737890A
Publication Date:
August 07, 1992
Filing Date:
October 03, 1990
Export Citation:
Assignee:
ASAHI OPUTEIKARU KK
International Classes:
G02B3/02; B29D11/00; G02C7/02; (IPC1-7): G02B3/02; G02C7/02
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